1. Field of the Invention
The present invention relates to improvements for controlling a filter system in use as well as a corresponding filter cartridge, which is used for filtering or which is under test, with respect to its permeability. Accordingly, the invention relates to the corresponding filter cartridge and a filter element attachment, which can be attached a filter element to form the filter cartridge.
2. Description of the Related Art
As it is known from document U.S. Pat. No. 4,384,474 A at least one membrane filter cartridge can be installed in a filter testing device in order to test the integrity of the membrane filter cartridge. The filter testing device comprises a sight glass which is arranged to observe gas bubbles in an outlet, when air pressure is applied to the filter cartridge and the air is leaking through an defective part of the membrane filter cartridge. However, the filter cartridge itself is hidden in the filter testing device and an user of the filter testing device has to mark or register manually whether the filter cartridge has passed or failed the test.
Thus, an object of the present invention is to propose a filter element attachment, a filter cartridge and a filter system that allow an improved monitoring of a filter element test and an improved handling of the filter cartridge and the filter system.